Months after the Camp fire ravaged Paradise, California the states deadliest and most destructive fire ever the town is now facing another problem: Its water is contaminated with cancer-causing benzene.

In a report last week, water officials said the full extent of the contamination is not yet known and laid out a long and expensive process needed to test and clear the system before water would be safe for drinking.

In an earlier February notice, Paradise Irrigation District officials said that the areas water quality was severely compromised due to fire damage. Officials said that about 40% of the water service lines theyd tested had shown signs of contamination, with the most prevalent chemical being benzene. (Long-term exposure to high levels of benzene can lead to anemia and leukemia, per the Centers for Disease Control and the World Health Organization.)

Paradise water is not safe to drink , the notice read, warning residents to use bottled water for cooking and brushing teeth.

Officials told the Sacramento Bee they had tested around 500 water samples in the area and found benzene about a third of the time. Its not clear how much of the towns water system may have been affected, as only about 2% of the system has been sampled, reported NPR.

After the fire leveled Paradise, killing 85 people and destroying nearly 14,000 homes , it displaced most of the residents who then moved to nearby Chico or left the area or the state altogether.

Of about 27,000 people living there before, only some 1,500 remain in the houses left standing, per the Associated Press. They now rely on bottled water and water tank deliveries.